Apparatus for roasting coffee



Aug. 3, 1943.

C; E. CUSACK ET AL APPARATUS FOR RASTING COFFEE Filed Oct. 8, 1940 7 Sheets-Sheet l Aug. 3, 1943. c. E. cusAcK ET AL. 2,326,094

APPARATUS FOR ROASTING COFFEE Fild oct. 8, 1940` 7 sheets-sheet 2 FIG. 3

"In Ihn 52 Aug. 3, 1943. c. E. cusAcK ET Al.

APPARATUS FOR ROASTING COFFEE Filed Oct. 8,` 1940 7 Sheets-Sheet 5 Aug. 3, 1943.` c. E. cusAcK ETAL APPARATUS FoR RoAsTING COFFEE 1940 '7 Sheets-Sheet- 4 Filed ot. 8

Aug 3, r1943. c, E. cusAcK x-:T Al. 2,326,094

APPARATUS FOR ROASTING COFFEE Filed Oct. 8, 1940 7 Sheets-Sheet 6 /f-I 66 7p l :.r-

/4 zza 255 7p /257 25/ Jullln I (D @/Z v 276 M w "ullh,a il c5 if 2/ "Imm" l @J Aug. 3, 1943. c. E. cUsAcK ET AL APPARATUS FOR ROASTING COFFEE Filed Oct. 8, 1940 7 Sheets-Sheet 7 Patented Aug. 3, 1943 APPARATUS FOR ROASTING COFFEE Charles E. Cusack and Hans l. Berger, Los

Angeles, Calif., assignors to The McCass Company, Los Angeles, Calif.

Application October 8, 1940, Serial No. 360,308

12 Claims.

This application relates generally to the roasting of food stuffs and more particularly to a novel apparatus for roasting coffee berries and the like.

'I'he practice generally followed in merchandising coffee is to roast large quantities of green coffee in roasting plants and package the roasted coffee for retail distribution. A major problem encountered in this practice is that of maintaining as much of the flavor of the coffee as possible during the time between the roasting process and the consumption of the coffee.

After the coffee berries are harvested and treated for shipment, they may be stored for a considerable length of time before roasting. Green coffee berries ready for roasting are considered to be stable and after roasting they are considered as perishable. Great care is exercised in processing and marketing coffee to decrease the deterioration thereof. Expensive machinery and packaging processes are extensively employed for the purpose of retaining as much of the flavor of the coffee as possible during the time between roasting and ultimate consumption.

In order to overcome the problems involved in the above practice, ,it is an object of our invention to provide a coffee roaster suitable for use by the retail merchant to roast coffee as ordered by the consumer.

Another problem encountered in the coffee industry is that of roasting the berries to the proper degree. Different kinds and different blends of green berries require dierent roasting periods, the roasting usually being done by highly skilled experts who can determine when the various types of coffee are properly roasted by the color of the berries, aroma, and the sound of berries being roasted.

It is,` accordingly, another object of our invention to provide a coffee roaster which may be operated by an unskilled operator to properly roast any kind or most blends of berries.

In order to enable the retail merchant to roast coffee as ordered, it is essential that the roasting take as little time as possible. The most commonly used methods of roasting require about twenty minutes per roast which is too long to enable the retail merchant to do the roasting.

It is another object of the present invention to provide an apparatus for roasting coffee in a much shorter time than previously required.

A further object of our invention is the provision of a coffee roaster combined with a cooling unit to enable cooling the roasted berries immediately after roasting for the purpose of arresting the roasting process and to permit packaging the coffee immediately after roasting.

Still another object of the present invention is the provision of a coee roaster in which means is provided for separating the chaff from the berries during the roasting process.

Another object of our invention is the provision of a combined roasting and cooling unit in which the operation is entirely automatic from the time the berries are introduced into the roasting unit until they are discharged from the cooling unit.

Other objects and advantages will become apparent in the following description taken inview of the accompanying drawings in which: t

Fig. 1 is a plan view of a preferred form of coffee roasting apparatus of our invention.

Fig. 2 is a fragmentary vertical sectional view taken on the line 2-2 of Fig. 1.

Fig. 2A is a fragmentary vertical sectional view similar in part to Fig. 2 showing diagrammatically the manner in which material being roasted circulates within the roasting chamber of the apparatus of our invention.

Fig. 3 is a vertical sectional view taken on the line 3-3 of' Fig. 1.

Fig. 4 is a fragmentary vertical sectional view taken on the line 4-4 of Fig. 3.

Fig. 5 is a fragmentary vertical sectional view taken on the line 5-5 of Fig. 3.

Fig. 6 is a horizontal sectional View taken on the line 6-6 of Fig. 3.

Fig. l is a fragmentary sectional view showing the closed position of a door shown in Fig. 6.

Fig. 8 is a horizontal sectional view taken on the line 8-8 of Fig. 3.

Fig. 9 is a fragmentary sectional view showing a portion of the mechanism shown in Fig. 8 and the manner in which this mechanism operates.

Figs. 10 and 11 are horizontal sectional views taken on the lines lill0 and II-II respectively of Fig. 3.

Fig. 12 is a fragmentary vertical sectional view taken on the line I2-I2 of Fig. 1.

Fig. 13 is a fragmentary vertical sectional view taken on the line l3--I3 in Fig. 12.

Fig. 14 is a wiring diagram of the coffee roaster of our invention.

Fig. 14A is a fragmentary diagrammatic view showing a portion of the wiring diagram of a slight modification of the apparatus of our invention.

Fig. 15 is a side elevational view of a control unit for use in connection with our invention.

Fig. 16 is a plan view of the control unit shown in Fig. 15.

Fig. 17 is a vertical sectional view taken on the line |1-I1 of Fig. 15.

Figs. 18, 19, and 20 are vertical sectional views taken on the lines I8-I9, |9-|9, and 20-20 respectively of the Fig. 16.

Referring specifically to the drawings, a coffee roaster I of our invention is'shown generally in Fig. 3. The roaster |0 includes a frame II, a cooling unit I2, a roasting unit I3, and a control unit I4.

The frame I I comprises a circular base 20, having legs 2| thereon and formed to provide an opening 22 shaped as seen in Figs. 3 and 11. Fixed on the base 20 is a circular housing 25 having openings 26 on top as seen in Figs. 1 and 3. Mounted above the housing 25, by means of rods 30 and spacers 3|, are spaced plates 32, 33, and 34.

Cooling um't 12 The cooling unit I2 includes an annular wall 40 mounted within the housing 25 as shown in Figs. 3 and 11. Mounted on the lower extremity of the wall 40 by means of hinges 4| and 42 is a pair of doors 43 and 44. These doors, as seen in Fig. 11, are semicrcular in shape andare made of suitable frames tov which metal screen 45 is' secured. Fixed on the hinge 4I- as shown in Fig. 3, is a finger 46 which moves with the door 43 in a manner and for a purpose to be described hereinafter. As shown in Fig. 1l, fingers 48 are fixed at opposite sides of the door 43, these fingers being disposed beneath pins 49 which are attached to the door 44. When, as later described, the door 43 is lowered to open position or raised to closed position, the door 44 is also opened and closed by means of the fingers 48 and pins 49.

Positioned within the housing 25, as seen in Figs. 3. 4. and 11. is a magnetically operated latch 52. The latch 52 includes a coil 53 having a C-shaped core 54, the latter being supported on the Wall 40 by pins 55 shown in Fig. 4. Pivotally mounted to one pole of the core 54 is a keeper 56 notched to receive an extension 51 formed on the door 43.- The keeper 56 is normally retained in the position in which it is shown in Fig. 4 by a spring 58 and a stop 59. The lower end of the keeper 56 is so shaped as to permit the door 43 to rise into engagement therewith.

Also included in the cooling unit I2 is a blower 65 having a rotor 66 and a housing 61, the latter having an intake mouth 68 formed at the lower side thereof. The blower housing 61 is suitably mounted on the housing 25 as shown in Figs. 3 and 10. The blower 65 has a discharge mouth indicated at in Fig. 10. Extending vertically from the discharge mouth 10 of the blower housing 61 is a vertical exhaust pipe 1|, the latter being rectangular in cross section and extending from the blower 65 upward to the top of the coffee roaster I0.

As seen in Figs. 12 and 13. the upper extremity of the exhaust pipe 1| is closed by a semicrcular top 12. A vertical slot 13 is formed in a wall of the pipe 1 I, as seen in Fig. 13, this slot being covered by a vertical series of louvers 14. Formed in another wall of the pipe 1| is-an opening 15 there being a wall 16 mounted within the pipe 1 I. Removably mounted in the opening is a chaff trap 11, the latter having a cylindrical screen 18 which is open at its upper end to receive airy blown upwardly through the pipe 1|. The trap 11 has an air outlet opening 19 and a handle 80.

Roasting unit 13 The roasting unit I3 is formed byspaced inner andv outer walls 90 and 9| respectively these being disposed between `the plates 33 and 34 to form a roasting chamber'C as seenin Fig. 3. The inner wall 90 is formed to provide an outlet opening 92, .the latter being opened and closed by means vof a door 93, as seen in Figs. 6 and 7 respectively. The door 93 is hinged at 94 and is providedwith a ridge 95 which is vertically disposed and coextensive with the height of the door 93 the purpose of the ridge 95 being explained f later. Mounted on the .outersde of the `door 93 is a cam 91. Fixed on the inside surface of the inner wall 90, as shown in Figs. 6 and 3, is a vthermostatic element |00 the latter controlling an adjustable thermostatic switch element I0 Iby means of a liquid filled tube, or the like, |02.

Mounted centrally on the underside of the plate 34 is an electric heating element |06, the latter being concentrically disposed within the roasting unit I3. Formed vertically through the wall 90, as shown in Fig. 6, is a slot |08, the latter communicating with the slot 13 of-the exhaust pipe 1 I Rotatably mounted in the plates 32 and 33 is a vertical shaft |I0 the latter having a cup shaped rotor I I fixed on the upper end thereof. Formed on the upper face of the rotor I I I is a transverse n ||2. Fixed on the lower end of the shaft ||0 is a gear I I3 which meshes with a pinion I |4 provided on the shaft ||5 of an electric motor ||6. The motor ||6 is bolted to the under side of the plate 32. The lower end of the motor shaft ||5 serves to drive the rotor 66 of the aforedescribed blower 65.

Mounted on top of the plate 34, as shown in Fig. 2, is a cap |20. vThe space between the cap |20 and plate 34 as well as the -space between the side Walls and 9| of the roasting unit I3 is lled with heat insulating material |2| for the purpose of conserving heat within the roasting unit I3. Formed in the plate 34 and cap |20 are aligned openings |24 and |25, the latter having a hopper |26 mounted therein.

The lower surface of the plate 34, the inner surface of the wall 90, and the upper surface of the rotor III are preferably gold plated for the purpose of efficiently reflecting the heat rays radiated from the heating element |06,-

As shown in Fig. 2, a rotatable rod |30 extends through the plates 32, 33, 34, and the cap |20. The upper end of the rod |30 is bent to provide a handle |3| to permitmanual oscillation of this rod. Fixed on the rod |30, between the cap |20 and plate 34, is a shutter |32 which is normally disposed in closing relation with the lower end of the hopper I 26 as shown in Figs. 1 and 2. Fixed on the plate 34 is a stop pin |33.which stops the shutter |32 in closed position. Fixed on the rod |30 is a torsion spring |34 which urges the rodv |30 in a clockwise direction, 4as viewed in Fig. 1, so as to urge the shutter |32 against the stop |33.

Fixed on `the control rod |30 between the plates 32 and 33, as seen in Figs. 2, 8, and 9, is a collar |31 having -arms |38 and |39. Mounted on the plate 32 is a pair of switches |40 and |4| these being normally open. These switches are positioned so that one or the other is closed by the extension |38 of the collar |31 when the latter isin either of the positions shown in Figs. 8

and 9.

Adjacent the control rod |30 is a secondary control lrod 45 this rod b'eing shown in Figs. 3, 6 to 9 inclusive, 10 and 11. The rod |45 is coextensive with the height of the main portion of the roaster I0, the lower end of this rod being journaled in the base 20, as seen in Fig. 3, while the upper end thereof is journaled inv the uppermost plate 34. Fixed on the lower end of the secondary control rod |45, as shown in Figs. 3 and 11, is a collar |48 having fingers |49 and |50 extending laterally therefrom. The nger |49 is curved, as seen in Fig. 11, and positioned to engage the finger 46 of the door 43 of the cooling unit I2. The nger |50 is attached to an extension spring |5| the latter being provided for the purpose of urging the rod |45 counterclock- Wise to the position in which it is shown in Fig. 11. As seen in Figs. 8 and 9, an arm |55 is xed on the rod |45, the arm |55 having a pin |56 extending from one side thereof. The Iarm |55 is urged to the position in which it is shown in Fig. 8 by the aforementioned spring |5| shown in Fig. 11. Mounted adjacent the arm |55 is a pair of switches |60 and |6| these being normally closed as seen in Fig. 9. These switches are simultaneously opened by the pin |56 of the arm |55 when the latter is in the position in which it is shown in Fig. 8.

Mounted on the plate 32 adjacent the arm |55 is a magnetic latching unit |65 having a coil |66, the unit |65 being similar in construction and operation to the aforedescribed magnetic latching unit 52 of the cooling unit |2. The latching unit i 65 functions to retain the arm |55 in the position in which it is shown in Figa 9 Iand to automatically release this arm as hereinafter described.

Shown in Figs. 6 and 7 is an arm |10 xed on the secondary control rod |45, this arm having a roller |11 mounted on its extremity. The roller l1! rides on the cam 91 of the door 93. the latter being urged rightward against the roller lll by an extension spring |12 which is hooked on the cam 91 and control rod`|l!5.

In Figs. 3, 5 and 6 to 9 inclusive a vertical pipe |15 is shown which extends downward from the opening 92 of the roasting unit i3 into communication with the cooling unit i2. As seen in Fig. 3. the pipe 115 is provided with e butter.- iiy valve |16 operated by a crank il?. Mounted on the housing 25 adjacent Athe pipe |15 is la butteriiy valve control unit |88. This unit includes a C-Shaped core 18| having a coil |82 thereon. Pivotally mounted on the upper pele of the core |81 is a lever |83 notched at its upper end to operably engage the crank |71 of the valve |16. Extending from the pipe |15 is a stop pin 85, the lever |83 being normally urged against this pin by an extension spring i86. 'I'he unit i 85 functions to close the butterfly valve |16 when the coil |32 is deenergized, as seen in Figs. 3 and 5, and to open this valve when the coi?, |62 is energized.

Control unit 14 Reference is now made to Figs. l5 to 20 of the drawings in which the control unit. ill of the coiee roaster l0 is shown. This unit is provided for the purpose of controlling the various electrical elements of the coffee roaster and may be used remotely or mounted directly on the frame il as preferred. The present -disclosure shows the unit |4 separate from the frame |and to bc used in remote relation to the roaster |0.

The control unit I4 includes a pair of side plates 260 and 20| these being secured in spaced 2|5, 2|6, 'and 2|1. Adjacent the collar 2|'I is' an element 220, as seen in Figs. 16, 17, and 18, this element being rotatably mounted on the shaft 2|0. The element 220 is formed to provide a gear wheel 22|, a cam 222, and a dial 223. The cam 222 is formed to provide a notch 224 as seen in Fig. 18. The dial 223 is graduated into sixty divisions each of these divisions indicating one second. The element 220 is urged against the collar 2|1 by a compression spring 226 positioned on the shaft 2|0 between washers 221 and 228. Rotatably mounted on the shaft 2|0 between collar 216 and washer 221 is a cam 230 having a notch 23| formed in its periphery as seen in Fig. 19.

The spring 226 urges the Vwashers 221 and 228 against the cam 230 and element 220, respectively.. This arrangement permits the element 220 to be manually rotated, as later described, while the cam 230 is held against rotation. The washers 221 and 228 are made of a material such as ber or the like having a relatively high coefficient of friction so that when the cam 230 is held against rotation during rotation of the shaft 2 0, the element 220 is also held against rotation by the spring 226 and washers 221 and 228. When the cam 230 is permitted to rotate with the shaft 2 0, as hereinafter described, the element 220 also rotates.

Rotatably mounted on the shaft 2|0 adjacent the collar 2| 5 is a cam 234 having a notch 235 formed in its periphery as shown in Fig. 20. Pivotally mounted on the cam 2341 is a guard plate 236 pivoted at 231. Extending from the cam 234 is a pin 238 to which one end of an extension spring 235| is fixed, the opposite end of this spring being attached to the guard 236. The spring 23S tends to urge the guard 236 rightward, as viewed in Fig. 20, to the dotted line position with the riglitmost edge of the guard 236 engaging the 19in 238.

On the shaft 2|0 adjacent the cam 234 is a Washer 221 and a spring 226', the latter urging the cam 231i against the collar 2|5 so as to frictionally connect the cam 236 and shaft 2|0.

Pivoted on a rod 240 extending between the plates 200 and 20| are three levers 28|, 242, and

, 253 these being disposed in radial alignment with the cams 222, 230 and 23B respectively. The three levers are positioned on the rod 240 by means of collars 246 and spacers 241. Each of the levers 24|, 242, and 243 has a downturned end as seen in Figs. 18, 19, and 20.

Fixed on the bar 266 in alignment with the lever 261i is a switch 250 having upper and lower leaves 251 and 252 respectively as lseen in Fig. 18. The lower leaf 252 extends beneath one extremity of the lever 24|. Fixed on the leaves 25| and 252 are contact points 253. The switch 250 is normally closed and is opened by the lever 24| when the latter is in the position in which it is shown in Fig. 18. l

Mounted on the bar 206 in alignment with the lever 242 is a switch 256 having upper and lower leaves 251 'and 258, as shown in Fig. 19, the leaves 251 and 258 having contact points 259. The upperA leaf 251 extends over the extremity of thelever 242 and is engaged thereby as seen in Fig. 19. 'I'he switch 256 is normally closed and is opened when the downturned end of the lever 242 drops into the notch 23| of the cam 230. Fixed on the bar 206 is a third switch 260 positioned in alignment with the lever 243. The switch 260 has upper and lower leaves 26| and 262 respectively and a pair of contact points 263. The lower leaf 262 of the switch 260 extends under the extremity of the lever 243. The switch 260 is normally closed and' is permitted to remain in closed position when the downturned extremity of the lever 243 drops into the notch 235 of the Ycam 234.

Mounted on the plates 200 and 20| is a transverse member 265 having a pair of magnets 266 and 261 mounted on the under side thereof. The magnet 266 is vertically aligned with the lever 242 while the magnet 261 is vertically aligned with the lever 243. Also mounted on the member 265 is a pointer 210 the latter extending into close proximity with the periphery of the graduated dial 223.

Rotatably mounted on the plate 20|, as seen in Fig. 16, is a shaft 214 having a beveled pinion 215 fixed on its inner end and a nob 216 ilxed on its outer end. Mounted onv the shaft 214 between the .plate 20| and the nob 216 is a compression spring 218. In addition to being rotatable, the rod 214 is slidable axially to permit pushing the rod inward until the pinion 215 meshes with the gear 22| of the member 220. Rotation of the shaft 214 while in the inward position imparts rotation to the member 220 for a purpose to be described hereinafter.l

Reference is now made to the wiring diagram shown in Fig. 14. Electric current is supplied from a suitable source to the various electrical elements of our invention by means of lead wires 290 and 29| which pass through a main switch S. The lead wire 29| extends to one terminal of the heating element |06, the opposite terminal of this heating element being joined by a wire 292 with the contact of a switch 293 of the thermostat I the switch 293 being thermally controlled in accordance with the temperature of the thermostatic element |00 and setting of the thermostat |0I. The lead wire 290 extends to the arm of the switch 293, it being clear that whenever the switch 293 is closed the heating element |06 is energized.

The remaining circuit is controlled by a relay 295, the latter comprising a coil 296, a switch 291 having an arm 298 and contact point 299. A wire 300 connects the contact point 299 of the relay 295 with the lead Wire 290. The coil 296 of the relay 295 is joined to the lead 290 by a wire 305 and to the switch |40 by a wire 306. Extending from the opposite side of the switch |40 is a wire 301 which extends to a wire 308 which connects one side of the switch |60 to the arm of the switch 256. The contact of the switch 256 is connected by a wire 309 to the remaining side of the switch |60 it being noted that the wire 309 is joined to the lead wire 29|.

The main drive motor H6 is connected to the lead 29| by a wire 3|2 and to the arm 298 of the relay switch 291 by a wire 3|3, the motor H6 being thus controlled by the relay. The synchronous motor 2li of the control unit 4 is connected to the lead wire 29| by a wire 3|6 and is connected by a wire 3|1 to the wire 3| 3. The switch |4| is connected by a wire 3| 8 to the lead wire 290 and the opposite side of the switch I4l is joined by a wire 3I9 to one terminal of the coil 261 of the control unit I4. The opposite terminal of the coil 261 is connected to the lead 29| by a wire 320.

The switch |6| is connected by a wire 324 to one terminal of the coil 266 of the control unit I4, the remaining terminal of the switch |6| being joined with one terminal of the heating element |06 by a wire 325. The coil |66 is joined in parallel by wires-329 and 330 with the coil |82 of the butterily valve control unit |80. The wire 329 is connected to a wire 33| which extends to the arm of the switch 250 oi' the control unit i4. The wire 330 is joined to the lead 290 by a wire 332. One terminal of the coil 53 ofthe latch unit 52 is connected by a wire 335 to the wire 324, the opposite terminal of this coil being joined by a wire 336 to the contact of the switch 260 of the control unit |4.

Connecting the wire 336 with one terminal of the coil 266 of the control unit |4 is a wire 338. The contact point of the switch 250 of the control unit i4 is connected with the lead 29| by a wire 340. Extending from the arm of the switch 260 of the control unit |4 to the wire 3| 1 is a wire 342.

Operation Prior to a detailed description of the operation of the method and apparatus of our invention, the general mode of operation will be pointed out so that the detailed description of the operation may be more readily understood.

The rotor III of the roasting unit I3, during operation of the roaster |0, is preferably driven at a speed suilicient to throw the coifee berries from this rotor and cause them to climb the in- -ner wall 90 in a spiral path. In practice a speed of approximately 800 R. P. M. of an eight inch diameter rotor has been found suiicient to throw theberries in this manner. This action causes the mas's of coffee berries within the roasting unit' I3 to substantially cover the inner surface of the wall 90. As the mass of berries moves rapidly about the inside of the wall 90, the vertical ridge 95 on the door 93 deflects the berries from their normal path within the roasting unit.

The movement of the coilee berries within the roasting chamber C, during operation of the roaster i0, is diagrammatically illustrated in Fig. 2A. In this view the rotor is understood to be rotating at approximately 1500 to 1700 peripheral feet per minute in the direction indicated by the arrow a. A mass of coffee berries being roasted is suspended within the chamber C in an annular shape S having an approximate cross-sectional formation as defined by the dotted lines in Fig. 2A'. The horizontal dotted line b denes the approximate uppermost extent of the annular shape S while the horizontal dotted line b defines the approximate lowermost extremity of the shape S. As illustrated, the lower edge of the annular mass of berries extends only slightly below the upper edge of the fin 2.

The coiee berries follow substantially the path indicated by the short arrows d within the shape S. Starting at the bottom, the berries are engaged and rotated by the iin ||2 of the rotor III. The centrifugal force acting on the berries thus engaged, causes them to ascend the Wall in a helical path, their speed reducing as they ascend toward the uppermost extremity b of the annular shape S. At this point, the -berries begin their downward movement and are displaced inward from the wall 90 by other rising berries.

'I'he vertical ridge 95, see Figs. 2 and 7, deilects the berries from their normal path of movement about the wall 90. The effect of the ridge 95 is to loosen up the mass of berries comprising the shape S and to slow the rate of travel of the berries which results in less time being required for the berries to progress from the rotor III to the top of the shape S and back to the rotor again. The ridge 95 also functions to turn the individual berries over and prevent the berries, which are somewhat flat on opposite sides, from riding up the wall with the same side of each berry disposed against the wall 90.

The downward movement of the berries takes place substantially on the inner diameter of the annular shape S. It is during this downward movement that the berries are exposed to the maximum amount of radiant heat from the element |06. As the berries circulate in the direction indicated by the short arrows d in Fig. 2A, they are also rotating about the heating element |06 so that the actual path followed by the berries is helical. i

While the coffee berries are circulating as above described, the atmosphere within the chamber C is also circulated by the rotor III in the path indicated by the long arrows e in Fig. 2A. A reduced pressure area at the center of the rotor III draws heated atmosphere down from about the heating element |06 and forces this heated atmosphere outward and upward through the mass S of cofleeberries. Thus the hottest atmosphere within the chamber is effectively forced through the coffee berries.

This method of circulating coffee berries during the roasting process has proven highly satislactory. The berries are moved rapidly at all times which prevents any one berry from being overexposed to the heating element. This rapid movement also dissipates the i'ilm of gas which forms about each berry during the roasting process.

When stationary coffee berries are subjected to the intense radiant heat from the element |06 without b'eing circulated so as to dissipate the gas film tending to surround each berry, the outer surfaces of the berries are burned and the center portions are under-roasted. The theory supporting this fact is that radiant heat from the element |06 readily passes through the gas film Y to the coffee berry and quickly heats the outer surface of the berry. The heat thus transmitted to the surface of the berry cannot escape outward from the berry by convection except; at a very slow rate due to the high insulating property of the gas film surrounding the berry. As the rate of conduction of heat from the surface toward the center of the berry is relatively slcw, the surface is scorched or over-roasted while the center remains under-roasted. Thus, when the gas lm is substantially and continuously dissipated as by applicants roaster, the berry surface is protected against scorching because the excess neat from the surface is free to transfer to the atmosphere within the roasting chamber.

During the period when the heating element |06 is fully energized, the heat transferred to the coffee berries is conducted from the outer surfaces of the berries to the center thereof, the outer surfaces being protected against scorching by removal of the gas film as described.

It will be noted in Figs. 3 and 6 that the heat responsive element |00, which is connected with the thermostatic switch |0I, is so positioned within the roasting unit I3 as to offer as little obstruction as possible to the circular movement of the berries as they move along the wall 90.

During the roastingprocess the element |00 is substantially covered by the coffee berries disposed against the wall 90 thus protecting the element |00 from the heat radiated from the heating element |06.

As the element |00 is covered by the mass of berries circulating within the roasting unit I3, the temperature within this unit rises to a much higher degree than when the roasting unit I3 is empty thus subjecting the berries to a high temperature which accomplishes the first stage of the roasting process, that of dehydrating the berries, in a relatively short time.

When the temperature of the mass of berries in the roasting unit I3 rises to a predetermined point, the thermostatic switch IOI breaks the main circuit (wires 290,29I, and 292) to the heating element |06. ries are substantially dehydrated and darkened in color so as to absorb heat very readily. The control unit I4 now functions in response to the breaking of the main circuit of the heating element |06 to open the door 93 of the roasting unit I3 when a given period of time has elapsed from the breaking of said main circuit. During this given period of time the final and most critical part of the roasting process occurs.

When the door 93 opens, the rotor III quickly throws the berries through the opening 92 and down the pipe |15. The butterfly valve |16, which is normally closed, prevents the suction of warm air downward from the roasting unit I3 into the cooling unit |2. Simultaneously with the opening of the door 93, the magnetic control unit functions to open the butterfly valve |16 and permit the roasted berries to gravitate onto the screen doors 43 and 44 of the Cooling unit I2.

At a predetermined time after the passage of the berries into the cooling unit I2, the magnetic latch 52 is energized permitting the doors 43 and 44 to open downward to dump the cooled berries through the opening 22 of the base 20 into a suitable receptacle (not shown). The doors 43 and 44 of the cooling unit I2 are closed automatically, as later described, upon the introduction of a subsequent batch of green berries into the roasting unit I3.

The manner in which the various mechanical and electrical elements of the apparatus of our invention function to accomplish the above described mode of operation is as follows:

The first step in operating the coee roaster I0 of our invention is to close the main switch S which immediately energizes the heating element |06 located in the roasting unit I3. This heating element remains energized when the roasting unit I 3 is empty until the temperature within the `roasting unit I3 rises sufficiently to open the switch 293 of the thermostat |0I so as to break the main circuit to the heating element I 06. When a quantity of coffee berries is being roasted in the unit I3, the heating element I 05 remains energized until the temperature of the berries being roasted rises to a predetermined degree. thermostat IOI may be set at 300 to 400 degrees Fahrenheit to produce satisfactory results.

The dial 223, or the thermostat IOI, is now adjusted, if necessary, to determine the length of a period during which the berries are retained in the roasting unit I3 after the supply of current to the heating element |06 is reduced.

The dial 223 is rotated by pushing in on the nob 216 until the gears 22| and 215 mesh and then rotating the nob 216 to obtain the desired At this time the coffee ber- It has been found in practice that the' adjustment. It is to be noted that the gear 22|,

the dial 223, and the cam 222 all rotate together bers on the dial 223 indicate the length of time required for the downturned end of the lever 24| to drop into the notch 224 when the element 220 begins rotation.

During the operation of the coffee roaster I0, the only time that the dial 223 need be adjusted is to vary the degree to which the coffee is roasted. If a dark roast is preferred, the dial 223 is adjusted to increase the length of time that the berries remain in the roasting unit after the reduction of current to the heating element |06. If a light roast is preferred, the dial is rotated so as to decrease the roasting period. In addition to adjusting the dial 223 to vary the color of the finished roast, similar results can be obtained by adjustments of the adjustable thermostat |I. When the thermostat |0I is adjusted to increase the temperature at which the main circuit of the heating element |06 cuts out, the temperature within the roasting unit I3 is raised correspondingly which results in a dark roast. Likewise, opposite adjustment of the thermostat IOI results in a lighter roast.

After the dial 223 is thus adjusted, the green coffee berries to be roasted are dumped into the hopper |26, and the lever |3I on the upper end of the control shaft |30 is swung in a counterclockwise direction, as viewed in Figs. 1 and 14, thus swinging the shutter out from under the hopper |26 and permitting the berries to fail into the roasting unit I3 and onto the rotor I I. When the lever I3I and shaft |30 are rotated in this manner, the lever |38, shown in Figs. 8 and 14, swings out of engagement with the switch |40 and into engagement with the switch I4| as shown in Fig. 9. It will be noted in the Wiring diagram shown in Fig. 14 that when the switch I 4I is thus closed, the circuit to the magnet 261 of the control unit I4 is thus closed causing the lever 243 to be lifted by this magnet out of engagement with the periphery of the cam 234. When the lever 243 is thus lifted, the normally closed switch 260 is opened for the purpose of breaking the circuit to the magnet 266 of the control unit I 4 so as to render the magnet 266 inoperative until the switch 260 is again closed.

When the lever 243 is lifted by the magnet 261, the guard plate 236 of the cam 234 swings rightward from the solid line position in which it is shown in Fig. 20 to the dotted line position shown therein. As the magnet 261 is only momentarily energized as a result of the momentary closing of the switch I 4I, the lever 243 is vimmediately dropped after being lifted, this occurring when the shaft I 30 is permitted to return to its normal position shown in Fig. 14. It will be noted in Fig. 20, that when the lever 243 is dropped the guard 236 prevents the downturned end of the lever 243 from reenterng the notch 235. The end of the lever 243, while resting on the upper edge of the guard 236, does not prevent the cam 234 from rotating when the shaft 2 I 0 begins its rotation.

By comparing Figs. 8 and 9, it will be seen that when the rod |30 is rotated counterclockwise to allow the berries to pass from the hopper |26 into the roasting unit I3, the finger |39 on the rod 30 engages the arm I 55 and swings the latter from position in which it is shown in Fig. 8 to that shown in Fig. 9. This motion of the arm |55 rotates the secondary control rod |45 clockwise and allows the switches |60 and |6| to assume their normal closed positions. The arm |55 is now latched in the position shown in Fig. 9 by the magnetic latch |65. As soon as the coffee berries pass from the hopper |26 into the roasting unit I3, the lever I 3| is allowed to return to its normal position and is urged toward this position by the torsion spring |34, shown in Fig. 2. The shutter |32 is now again positioned in closing relatsion with the discharge outlet of the hopper I2 Referring to Fig. 14, it will be noted that upon the return movement of the control rod |30, the arm |38 again engages and closes the switch |40 which completes the circuit to the coil 296 of the relay 295. This circuit is completed through the switch |60 which, although shown open in Fig. 14, is closed following the latching of the arm |56 just described. When the relay 295 is thus energized, the switch arm 291 thereof closes against the contact 299 completing the circuit to the main drive motor II6 and the synchronous motor 2| I.

When the arm |55 is engaged and moved by the arm |39, as just described, the rotation of the control rod |45 from the position shown in Fig. 8 to that of Fig. 9 swings the arm |10, shown in Fig. 6, to the position in which this arm is shown in Fig. 7. 'I'his closes the door 93 so as to retain the berries within the roasting unit I3, this action occurring just prior to the time the rotor III of the roasting unit I3 starts rotating.

By reference to Fig. 11, it will be seen that when the rod |45 is rotated clockwise, as just described, the curved finger |49 is swung rightward out of engagement with the finger 46 of the door 43, the latter being retained in closed position by the magnetic latch 52 It will also be noted in Fig. 11 that the clockwise rotation of the control rod |45 extends the extension spring I5I which serves to rotate the rod I 45 in a counterclockwise direction at a time hereinafter mentioned.

The various functions just described which occur in response to the opening and closing of the shutter |32 are reviewed in the following outline:

When the control rod |30 is rotated counterclockwise, as viewed in Figs. 1, 6, 8, and 14, the following functions are accomplished:

1. The shutter |32 (see Figs. 1, 2, and 14) is swung out from under the hopper |26 to permit the green coffee berries to gravitate into the roasting unit I3.

2. The switch |40, see Fig. 9, is allowed to open (the opening of the switch |40 having no function at this point in the operation).

3. The switch I4I, see Fig. 9, is momentarily closed by the finger |38 completing the circuit to the magnet 261 of the control unit I4 which results in the lever 243 being lifted from the notch 235 of the cam 234 and allowing the guard 236 to swing to the dotted line position in which this guard is shown in Fig. 20.

4. The arm |55 is swung clockwise and latched by the magnetic latch |65.

5. Energy is stored in the torsion spring |34 shown in Fig. 2.

When the rod |30 is permitted to rotate counterclockwise immediately following its clockwise rotation, the following occurs:

1. The switch I 4I is permitted to open as the arm |38 disengages this switch which results in breaking the circuit to the magnet 261 and allowing the lever 243 to drop on top of the guard 236. When the lever 243 drops on top of the guard 236, the switch 260 is held open to render the magnet 266 inoperative until the switch 260 is again closed.

2. The shutter |32 is returned to closing relation with the hopper |26.

3. The switch |40 is closed (see Fig. 14) energizing relay 295.

The functions of the rod |45 resulting from clockwise movement of this rod from the position shown in Fig. 8 to that shown in Fig. 9 are as follows:

1. The door 93 is closed as shown in Fig. '7.l

2. The extremity of the arm |55 engages the magnetic latch |65 to retain the arm |55 in the position shown in Fig. 9 thus holding the door 93 closed.

`3. The switches |60 and I6| are permitted to close, the switch |60 permitting the circuit to the relay 295 to be closed when the switch |40 is closed. The switch |6| completes the circuit to the magnet 266 ofthe control unit I4 and the magnet 53 of the magnetic latch 52. It is to be noted inthe wiring diagram of Fig. 14 that when the switch |6| is thus closed completing the circuit to the magnets 266 and 53 these magnets are not energized until the switch 293 of the thermostatic unit is opened.

4. The finger |49, see Fig. 11, moves out of engagement with the iinger 46.

When the motor I6 is energized by the closing of the relay 295, as aforedescribed, the rotor I|I is driven through the gearing I I3 and ||4 in a counterclockwise direction as indicated by the arrow in Fig. 6. The motor ||6 also drives the rotor 66 of the blower 65 in a clockwise direction l;

as viewed in Fig. 10.

The synchronous motor 2|| of the control unit I4 is also energized upon the closing of the relay 295 so as to drive the shaft 2I0 in a clockwise direction as viewed in Figs. 14, 18, 19, and 20. At this point in the operation the cam 230 is retained against rotation on the rotating shaft 2I0 by engagement of the lever 242 withthe notch 23| as seen in Figs. 14 and 19. The cam 222 is held against rotation by the cam 230 (these being frictionally connected by the spring 226 and Washers 221 and 228 as shown in Fig. 17). The cam 234, however, is permitted to rotate with the shaft 2I0 as the lever 243 is held out of engagement with the notch 235 by the guard lever 243 which rides on the periphery of the cam 234 during rotation of the latter engages the guard 236 pushing this guard leftward, as viewed in Fig. 20, to the solid line position. This allows the lever 243 to drop into engagement with the notch 235 so as to close the switch 260 and complete the circuit to the coil 266 and the coil 53 (these coils, however, are not energized at this moment and do not become energized until the switch 293 of the thermostat |0| opens breaking the main circuit to the heating element |06).

The purpose of providing the cam 234 to disconnect the magnet 266 for one minute is to prevent the magnet 266 from being energized until the heat responsive element I 00 is cooled by the introduction of a batch of berries to be roasted into the roasting unit I3. The cam 234, in other words, prevents the berries from being prematurely discharged from the roasting unit I3 should the switch 293 open in the event the roasting unit I 3 is hot at the time the unroasted berries are introduced therein. The berries are now continually circulated within the roasting unit I3 and subjected to the heat of the element |06 which remains fully energized until the temperature of the mass of berries within the roasting unit I3 rises sufficiently to open the switch 293 of the thermostat |0| by means of the element |00 and the tube |02 connecting this ele-l ment with the thermostat |0I.

Referring to Fig. 3, the blower 65 draws air downward through the holes 26 of the housing 25, this air passing through the screen doors 43 and 44 into the rotor 66 and is' discharged through the exhaust pipe 1 I. As shown in Figs.

12 and 13, the air moving upward through the pipe 1| passes over the louvers 14 into the cylindrical screen 18 and finallyout through the opening 19 of the chai trap 11. The passage of the air past the louvers 'I4 draws a small quantity of air from the roasting unit |3 through the slots |08 and 13 shown in Fig. 6. The chaff liberated from the colee berries during the roasting process passes through these slots into the stream of air within the pipe 1| and is trapped by the screen 18 of the trap 11. By means of the handle the trap 11 maybe readily removed when necessary to empty the chaff from the screen 18.

When the mass of berries within the roasting unit I3 is heated to a temperature corresponding with the setting of the thermostat, the heat responsive element |00, which corresponds in temperature to that of the berries, opens the switch 293' of the thermostat |01. Opening of the switch 293 breaks the main circuit'to the heating element |06 which allows the coil 266 of the control unit I4 and the coil 53 of the magnetic latch 52 to be simultaneously energized. When the magnetic latch 52 is energized, the lever 56 is swung out of engagement with the extension 51 of the door 43 permitting the latterv as well as the door 44 to swing downward into open position thereby dumping any berries previously roasted which may be disposed within the cooling unit I2.

When the coil 266 of the control unit I4 is energized, the lever 242 is lifted thus closing the switch 256 and permitting the cam 230 and the cam 222 to begin rotation. The closing of the switch 256 is for the purpose of maintaining the circuit to the relay 295 after the switch |60 is opened as presently described.

When the cam 222 rotates until the lever 24| drops into the notch 224, the switch 250 is closed which completes the circuit to the coil |66 and the coil |82. The coil |66, when energized, actuates the magnetic latch |65 causing the latter to release the arm |55 allowing this arm to return from the position shown in Fig. 9 to that shown in Fig. 8. This return movement of the arm |55 and control-rod |45 attached thereto is caused by the spring |5| shown in Fig. 11. This movement of the rod I 45, by means of the curved finger |49 and linger 46, automatically swings the doors 43 and 44 upward into closed position. Movement of the control rod |45, as seen in Fig. 6, also swings the arm |10 from the position shown in Fig. 7 to that shown in Fig. 6 permitting the spring |12 to open the door 93.

As the door 93 opens, the berries are thrown from the roasting unit I3 by the rotor I |I through the opening 92 into the pipe |15. As the coil |82 of the buttery valve control mechanism |80 is now energized, the lever |83, shown in Figs. 3 and 14, moves clockwise swinging the valve |13 from closed to open position to permit the roasted berries to pass into the cooling unit I2 where they are retained by the closed doors 43 and 44. The passage of cool air upward through the screen doors 43 and 44 rapidly cools the hot berries and arrests further roasting thereof which would result in over roasting of the berries.

When the lever 24| drops into thenotch 224 to close the switch 260 and energize the magnets |66 and |82, the cam 222 is not stopped by the lever 24|. The shape of the notch 224 simply permits the lever 24| to drop and then cams the lever 24| up to the position shown in Fig. 14.

The time required for the end of the lever 24| to pass into and out of the notch 224 holds the butterfly valve open for a sufficient period to allow all the roasted berries to pass from the roasting unit to the cooling unit.

At this stage of the roasting process the cam 230 and cam 222 continue to rotate until the lever 242 drops into the notch 23| of the cam 230 thus stopping the cam 230 and the cam 222. When the lever 242 drops into the notch 23|l the switch 256 is opened to break the circuit to the coil 296 of the relay 295 thus stopping the motors II6 and 2II.

This completes the roasting of a batch of berries with the exception of dumping the berries ,from the cooling unit I2. If a subsequent batch of berries is to be immediately roasted, these are placed into the hopper |26 and the operation previously described is repeated. When the roasting of this subsequent batch of berries progresses to the aforedescribed point at which the coil 266 of the control unit I4 is energized in response to the opening of the switch 293, the magnetic latch 52 functions to dump the cooled berries of the previous roast.

If it is necessary to dump a batch of cooled berries without roasting a subsequent batch of berries, the machine is operated just as though a batch of berries was being roasted and at the proper time in the cycle the magnetic latch 52 functions to release the doors 43 and 44 and discharge the batch of cooledberries.

In the use of the coifee roaster I it makes no diierence whether the roasting unit I3 is hot or cold at the start of the roasting process described; ne adjustments of the machine are required when the berries to be roasted are dumped into a cold or hot roasting unit other than thf adjustment of the dial 223 or thermostat |0I, in the event a darker or lighter roast is desired than that which the roaster is adjusted to produce.

The roasting process takes longer when the roasting unit I3 is cold at the time the berries are introduced therein than when the unit is hot, but the degree to which the berries are roasted is the same in either event. This is due to the fact that the critical period of the roast (the period between the shutting oi of the main circuit of the heating element |06 and the discharge of the berries from the roasting unit I3) is the same in either event.

Reference is now made to Fig. 14A in which we have shown a supplementary heating element |06', this element being connected to the main lead wires 290 and 29|. The addition of the heating element |06 comprises a slight modification in the apparatus of our invention, the purpose of which is to provide a roaster in which a relatively small amount of heat is supplied to the roasting unit after the larger heating element |06 is disconnected from the main circuit 75 by the switch 293 at the time the berries being roasted rise to the temperature at which the thermostat IOI is set.

As seen in Fig. 14A, the small heating element |03' is wired so as to receive current at all times when the main switch S is closed. In practice the small element |06' may be mounted at am suitabley point within the roasting unit I3 to produce this modification of our invention.

It has been found in practice that successive batches of green berries may be roasted in the roaster I0 of our invention to a constant degree or color regardless of the atmospheric temperature and humidity. It has also been found that the age of the berries to be roasted and the moisture content of these berries does not; aiect the color resulting from roasting such berries in this roaster. The constant results obtained, regardless of the above noted variable conditions, are due to the control of the heating elementl |06 in response to the temperature of the berries and to the method herein disclosed of retaining the berries within the roasting unit for a given period after interrupting the main supply of current to the heating element.v

If, for example, a dry batch of green berries is roasted, the time required to bring these up to the temperature at which the switch 293 is opened would be less than the time required in the case of a batch of berries having a high moisture content. The color or degree of roasting would be the same in either event.

'I'he rotor III, in addition to circulating the coiee berries within the chamber C, also functions to circulate hot air in this chamber. The fln II2 on the rapidly rotating rotor III throws air outward against the wall while reducing the pressure of the air in the region just over the center of the rotor. The air thrown outward travels up the wall 90 to the plate 34 where it moves inward and is drawn downward over the heating element |06 by the reduced pressure over the center of the rotor. Thus a continuous circulation of air is set up within the chamber C during the roasting process.

The hot air permeates throughout the mass of berries which results in an even distribution of heat to all the berries within the chamber C. This, in addition'to the aforedescribed manner in which the berries are circulated while being roasted, insures roasting each berry an equal amount. 1n actual practice, many successive batches of coilee b erries have been roasted in the roaster of our invention and, without exception, the berries were evenly colored indicating an equal absorption of heat by each berry.

Although we have shown but one preferred and one modiiled form of the apparatus and method of our invention, it is to be understood that many modifications and changes may be made therein without departing from the spirit of the invention or the scope of the appended claims.

We claim as our invention:

1'. In a roaster for coiree and the like, the combination of: a roasting chamber for receiving a quantity of material to be roasted, a pair of heating elements for heating said chamber and a thermostatic element for enabling and disabling one of said heating elements, said thermostatic element being so positioned in said chamber as to be insulated from the interior of said chamber by the material being roasted, said thermostatic element disabling said one of-said heating elements when the temperature of said material rises to a predetermined degree, the other of said heating elements maintaining the temperature within said chamber at a lower degree after the disabling of said one of said heating elements.

2. In a roaster for coffee and the like, the combination of: a roasting chamber for receiving a quantity of material to be roasted, said chamber having a discharge opening, a door for opening or closing said discharge opening, electric heating means, two circuits leading to said electric heating means. a. thermostatic element in the chamber for reducing the energy supply to said electric heating means when the temperature of the material being roasted rises to a given degree, means operated by said thermostatic element for interrupting one of said circuits to the heating means and rendering the second of said circuits leading to said heating means operative, and control means operated by the energy ilowing through the second of said circuits for opening the door of said discharge opening at the end of a predetermined period of time after said one of said circuits is interrupted.

3. In a roaster for coffee and the like, the combination of: a roasting chamber for receiving a quantity of material to be roasted, an inlet door for opening and closing the inlet opening of said chamber, an outlet door for opening and closing the outlet opening of said chamber, electric heating means, two circuits leading to said electric heating means, a thermostatic element in the chamber for reducing the energy supply to said electric heating means when the temperature of the material being roasted rises to a given degree, means operated by said thermostatic element for interrupting one of said circuits to the heating means and rendering the second of said circuits leading to said heating means operative, control means operated by the energy iiowini,r through the second of said circuits for opening the door of said discharge opening at the end of a predetermined period of time after said one of said circuits is interrupted, and means responsive to the opening of said inlet door for rendering said control means inoperative for a given period of time.

4. In a coffee roaster, the combination of: a` roasting chamber having inlet and outlet doors, means for heating said chamber to roast green coffee berries disposed therein, a thermostatic element in said chamber for controlling said heating means in accordance with the temperature of the berries in said roasting chamber, a motor, a rotary element driven by said motor in said chamber for circulating said berries during the roasting thereof, a switch for controlling said motor, means for opening and closing said inlet door, means operated by said means which opens and closes said inlet door for closing said outlet door in response to opening said inlet door, means operated by said means which opens and closes said inlet door for closing said switch and starting said motor when said inlet door is closed following the opening thereof, and control means responsive to said thermostat for opening said outlet door to permit the discharge of berries from said roasting chamber.

5. A combination as in claim 4 in which said control means opens said outlet door at the end of a given period of time after a control function of said thermostat.

6. In a coEee roaster, the combination of: a roasting chamber having inlet and outlet doors, means for heating said chamber to roast green coiee berries disposed therein, a thermostatic element 1n said chamber for controlling said said inlet door, means operated by said means` which opens and closes said inlet door for closing said switch and starting said motor when said inlet door is closed following the opening thereof, and control means responsive to said thermostat for opening said outlet door to permit the discharge of berries from said roasting chamber after the lapse of a given period of time after actuation of said control means by said thermostat, a cooling unit for receiving and cooling said roasted berries discharged from said roasting chamber, and means for automatically dumping the cooled berries from said cooling unit prior to the discharge of the next successive charge of coffee berries from the roasting chamber.

'7. In a roaster for coffee berries and the like, the combination of a roasting chamber having a top wall and a circular side wall, a rotary element mounted at the bottom of said chamber, iin means extending transversely on the upper side of said rotary element, power means for' driving said rotary element at a speed sufficient to impel coffee berries from said element and up said side wall in a spiral path, said berries being repeatedly thrown from said element as said berries decelerate suiliciently to fall from said circular wall to said element, and means for heating said chamber to a degree suilicient to roast said berries.

8. In a roaster for coffee berries and the like, the combination of: a roasting chamber having a top wall and a circular side wall, a rotary element mounted at the bottom of said chamber, iin means extending transversely on the upper side of said rotary element, powerameans for driving said rotary element at a speed suilicient to impel coiee berries from said element and up said side wall in a spiral path, said berries being repeatedly thrown from said element as said berries decelerate sufficiently to fall from said circular wall to said element, means for heating said chamber to a degree suilicient to roast said berries, and a thermostatic element in said roasting chamber for controlling said heating means, said thermostatic element being positioned relative to said heating means so that the coffee berries disposed against said circular wall are interposed between said heating means and said thermostatic element.

9. In a roaster for coiee berries and the like,

` the combination of a roasting chamber having a top Wall, a bottom wall, and a'circular side Wall, said chamber having a door to permit charging said chamber with a quantity of green berries to be roasted, a heating element mounted Within said chamber, means for rotating said quantity of berries in said chamber at sufficient velocity to cause said berries to cling by centrifugal force to said circular wall while moving rapidly about said heating element, and means on said circular wall to deflect the berries moving along said circular wall from the normal path of said berries.

l0. In a roaster for coffee berries and the like, the combination of: a roasting chamber having a top wall and a circular side wall, a rotor mounted at the bottom of said chamber and wall in a spiral path, a heating element mounted on said top wall and extending downward into A saidv chamber, and a thermostatic element mounted on said side wall for controlling said heating element, said thermostatic element being positionedy so as to be covered by said berries during the roasting process to enable said thermostatic element to control said heating element in responseto the temperature of said berries.

11. In a roaster for coiiee berries and the like, the combination of: a roasting chamber having v a top wail and a circular side wall, a rotary element disposed at the bottom of said chamber, tin means on said rotary element, means for driving said rotary element at a speed suicient to throw coiiee berries from said element and maintain said berries in an annular rotating mass against said circular side wall, said side wall having a discharge opening extending substantially from said rotary element to said top wall, and a door adapted to close and open said opening.

12. A combination as in claim 11 in which said door is hinged to said side wall at a vertical edge of said door, the direction in which said door extends away from said hinge being the same as the direction o! rotation of said rotary element.

CHARLES E. CUSACK. HANS H. BERGER. 

